<?php if($theme->getBootstrap() > 2): ?>
<div class="input-group">
  <input class="form-control" placeholder="<?php echo ucfirst($txt->getWord('text').' '.$txt->getWord('search')); ?>" type="text" name="q" onclick="this.value='';" value="<?php if($_REQUEST['q'] != '') { echo $_REQUEST['q']; } ?>" />
  <span class="input-group-btn">
    <button class="btn btn-default" type="submit" name="search"><?php echo ucfirst($txt->getWord('search')); ?></button>
  </span>
</div><!-- /input-group -->
<?php else: ?>
<div class="control-group">
    <div class="controls">
        <input class="input-medium" placeholder="<?php echo ucfirst($txt->getWord('text').' '.$txt->getWord('search')); ?>" type="text" name="q" onclick="this.value='';" value="<?php if($_REQUEST['q'] != '') { echo $_REQUEST['q']; } ?>" />
        <button type="submit" class="btn <?php echo $adc->getSetting('SearchBtnClass'); ?>" name="search"><?php echo ucfirst($txt->getWord('search')); ?></button>
    </div>
</div>
<?php endif; ?>